Bactericidal Activity and Poly-l-proline II Conformation of the Tandem Repeat Sequence of Human Salivary Mucin Glycoprotein (MG2)

Antonyraj, Kavitha J.; Karunakaran, T.; Raj, Periathamby Antony

doi:10.1006/abbi.1998.0779

Cited by 32 publications

(40 citation statements)

References 47 publications

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“…1B), and a shift to the right. A similar destabilizing effect of elevated temperature has been observed in other proline-rich peptides due to a transition from the PP II helical structure to a disordered random coil conformation (33). The CD spectrum of EL-CD28 peptide in 6 M CaCl 2 at 25°C exhibited a dramatic decrease in the intensity of the minimum at 205 nM ( ϭ Ϫ28 ϫ…”

supporting

confidence: 61%

A Retro-Inverso Peptide Mimic of CD28 Encompassing the MYPPPY Motif Adopts a Polyproline Type II Helix and Inhibits Encephalitogenic T Cells In Vitro

Srinivasan¹,

Wardrop²,

Gienapp³

et al. 2001

The Journal of Immunology

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Complete activation of T cells requires two signals: an Ag-specific signal delivered via the TCR by the peptide-MHC complex and a second costimulatory signal largely provided by B7:CD28/CTLA-4 interactions. Previous studies have shown that B7 blockade can either ameliorate experimental autoimmune encephalomyelitis by interfering with CD28 signaling or exacerbate the disease by concomitant blockade of CTLA-4 interaction. Therefore, we developed a functional CD28 mimic to selectively block B7:CD28 interactions. The design, synthesis, and structural and functional properties of the CD28 free peptide, the end group-blocked CD28 peptide, and its retro-inverso isomer are shown. The synthetic T cell-costimulatory receptor peptides fold into a polyproline type II helical structure commonly seen in regions of globular proteins involved in transient protein-protein interactions. The binding determinants of CD28 can be transferred onto a short peptide mimic of its ligand-binding region. The CD28 peptide mimics effectively block the expansion of encephalitogenic T cells in vitro suggesting the potential usefulness of the peptides for the treatment of autoimmune disease conditions requiring down-regulation of T cell responses.

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supporting

confidence: 61%

A Retro-Inverso Peptide Mimic of CD28 Encompassing the MYPPPY Motif Adopts a Polyproline Type II Helix and Inhibits Encephalitogenic T Cells In Vitro

Srinivasan¹,

Wardrop²,

Gienapp³

et al. 2001

The Journal of Immunology

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“…(4,(10)(11)(12) and antimicrobial proteins and peptides. These include lysozyme (13,14), lactoferrin (15,16), acidic proline-rich proteins (17,18), plunc (19,20), salivary mucin glycoprotein (16,21), histatin (13,17,22), defensin HBD1 (23,24), defensin HBD2 (25)(26)(27), defensin HBD3 (26,27), defensin HBD4 (26,27), and hCAP18/LL-37 (28). Fatty acids and long-chain bases found at the skin surface have strong bactericidal activity (29)(30)(31)(32)(33).…”

Section: Innate Immune Mechanismsmentioning

confidence: 99%

Thematic Review Series: Skin Lipids. Antimicrobial lipids at the skin surface

Drake

Brogden

Dawson

et al. 2008

Journal of Lipid Research

274

222

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The skin surface represents our interface with the external environment, and as such, is our first line of defense against microbial colonization and infection. Lipids at the skin surface are thought to underlie at least part of an antimicrobial barrier. Some of these lipids are synthesized in the epidermis and are carried to the surface as cells differentiate, whereas others are secreted onto the surface from the sebaceous glands. One such group, free sphingoid bases, are known to have broad antimicrobial activity, and our previous studies demonstrate their presence at the skin surface. Free sphingoid bases may be generated by enzymatic hydrolysis of epidermal ceramides. In addition, our preliminary results demonstrate potent antibacterial activity associated with two specific fatty acids derived from sebaceous triglycerides. Most remarkably, one of these fatty acids (sapienic acid, C16:1#6), in combination with a low concentration of ethanol, is very effective against methicillin-resistant Staphylococcus aureus (MRSA). In fact, this combination was far more effective than mupirocin with or without ethanol. Mupirocin is a "gold standard" for activity against MRSA.

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“…The cultivation of bacterial strains was carried out as described in our previous publications [35,36]. Briefly, Porphyromonas gingivalis strains W50 and 381 were maintained on blood agar plates containing tryptic soy agar (Difco Laboratories) supplemented with hemin (1%), menadione (0.02%) and de-fibrinated sheep blood (5%).…”

Section: Bacterial Strains and Cultivationmentioning

confidence: 99%

“…The bactericidal assays were performed as described previously [35,36]. The antimicrobial activity of defensins was tested against P. gingi.alis (W50 and 381), A. actinomycetemcomitans (Y4 and 67), S. gordonii (GS5) and S. mutans (DL1).…”

Section: Bactericidal Assaymentioning

confidence: 99%

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Large-scale synthesis and functional elements for the antimicrobial activity of defensins

Raj

Antonyraj

Karunakaran

2000

Biochemical Journal

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Human neutrophil defensins, and their analogues incorporating anionic, hydrophobic or cationic residues at the N- and C-termini, were synthesized by solid-phase procedures. The synthetic defensins were examined for their microbicidal activity against Candida albicans, two Gram-negative bacteria (Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis) and two Gram-positive bacteria (Streptococcus gordonii and Streptococcus mutans). The human neutrophil peptide 1 (HNP1) and HNP2 were found to be potent candidacidal agents. HNP3, which differs by one amino acid at the N-terminus of its sequence, was totally inactive. The Gram-negative bacteria A. actinomycetemcomitans and P. gingivalis and the Gram-positive bacteria S. gordonii and S. mutans were insensitive to human defensins. However, the insertion of two basic residues, such as arginine, at both the N-terminus and the C-terminus of HNP2 significantly enhanced antifungal and antibacterial activity. The addition of anionic residues, such as aspartic acid, at the N- and C-termini rendered the molecule totally inactive. The presence of two hydrophobic amino acids, such as valine, at the N-terminus of HNP2 and of two basic arginine residues at its C-terminus resulted in molecules that were optimally active against these oral pathogens. The results suggest that the N- and C-terminal residues in defensin peptides are the crucial functional elements that determine their microbicidal potency. The three-dimensional structure of all defensins constitutes the same amphiphilic β-sheet structure, with the polar face formed by the N- and C-terminal residues playing an important role in defining microbicidal potency and the antimicrobial spectrum. The enhanced microbicidal activity observed for defensin peptides with two basic residues at both the N- and C-termini could be due to optimization of the amphiphilicity of the structure, which could facilitate specific interactions with the microbial membranes.

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Bactericidal Activity and Poly-l-proline II Conformation of the Tandem Repeat Sequence of Human Salivary Mucin Glycoprotein (MG2)

Cited by 32 publications

References 47 publications

A Retro-Inverso Peptide Mimic of CD28 Encompassing the MYPPPY Motif Adopts a Polyproline Type II Helix and Inhibits Encephalitogenic T Cells In Vitro

A Retro-Inverso Peptide Mimic of CD28 Encompassing the MYPPPY Motif Adopts a Polyproline Type II Helix and Inhibits Encephalitogenic T Cells In Vitro

Thematic Review Series: Skin Lipids. Antimicrobial lipids at the skin surface

Large-scale synthesis and functional elements for the antimicrobial activity of defensins

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